Magnetic Trigger Devices Patents (Class 307/414)
  • Patent number: 4233529
    Abstract: In circuitry comprising a switching power output transistor stage and a driver transistor circuit, energy is stored in a magnetic circuit during the transistor on time to provide the turn off current. First and second magnetically coupled inductors are connected in series on the output of the driver transistor, and the base of the power transistor is connected to the junction point of the two series inductors. One or more diodes are connected in parallel with the first inductor to limit the potential drop across this inductor at turn on, and a parallel combination of at least one diode and a resistor is connected in series with the second inductor. The output stage may be two power transistors connected in a Darlington type configuration with a similar inductive circuit provided for each transistor.
    Type: Grant
    Filed: February 22, 1978
    Date of Patent: November 11, 1980
    Assignee: Thorn Automation Limited
    Inventor: Reginald H. Whitlock